image forensic - azibiki?
Certainly looks like the bamboo wrapped handle of a Japanese pull saw in the photo.
No blade showing, but it could be you have there a favorite of mine:
The Azibiki.
Seldom seen in catalogs or hardware stores.
Lee Valley carries one size. You have to go to the Japan Woodworker for selection.
The large size (5" blade, eg) would definitely be useful on your S-boat restoration. An amazing tool.
Known as a mortise saw, but I've used a small one for everything around the shop.
Every boat builder (indeed, every carpenter) should have one or three in his kit.
(Course it's not going to slice whiteoak like a bandsaw can!)
imco THE most versatile - and best kept secret - hand saw ever invented.:cool: